schnepf



Oct. 2, 1928. 1,686,037-

J. SCHNEPF RES ISTOR SUPPORT Filed June 24, 1927 INVENTOR Johann Schnepf.

Patented Oct. 2, 1928.

1011m 'scHN'EPryorjNUREMBERG, GERMANY,-' ASSIGNOR 'ro WESTINGHOUSE ELEC- A CORPORATION OF- PENNSYLVANIA.

. nnIRESISTOR SUPPORT.

Application.iiledilune l, tg1,'5 ea m. 201,289, and in Germany July 17, 192 s.

y. n n ate$ were; damr -P t ar yJaimieie ing an. l ctric r is a ce-has es. ele en e 9l "El:.:.,': Ris 51' "iv id zi In, electric resistor, furnaces, is. custom;

.ary to support the resistor :upqr tlrepwahs y m a s pp rt .-.preiec me t a th faces thereof view of therelat-ive ly high. temperatures attained in such furnaces t 1S,

necessary-that:the'snpports be made'of a refractory heat-resistant material which is usually ceramic.

Ceramic refractory supports, however, are usually of an acid characteristic becauw of the presence of silicic acid, and a chemical reaction between the support and metallic resistor results.

It is an object of the present invention, therefore, to provide in an electrical resistor furnace, means for preventing chemical reaction between the resistor and the resistor supporting means.

In one form of device embodying my invention, I provide an electrical resistance furnace comprising a metallic resistor supported by the walls of the heated chamber on refractory supports projecting therefrom, and a coating of material upon said supports for preventing chemical reaction between said supports and said resistor.

In the drawings, Fig. 1 is a lateral section through a resistance furnace embodying my invention,

Fig. 2 is a view in longitudinal section through a refractory resistor supporting block.

Referring more particularly to Fig. 1, the furnace embodying my invention comprises a plurality of built-up refractory walls 2 defining a furnace heating chamber 4.

Mounted in the side walls of said furnace chamber are a plurality of grooved supporting blocks 6, spaced to receive the upper ends of the convolutions of a preformed metallic resistance heating element 8, in supporting relation. The resistance element is forme of metallic refractory material, and preferably of a nickel-chromium-iron alloy.

A plurality of refractory blocks 10 are mounted in the furnace chamber side walls and are adapted to be received between the lower ends of the convolutions of resistor 8 to space the same along the furnace walls,

wee evaluate cir c'uiting thereo'f when heated. Y As shown more particularly in Fig.2 the resistorsupporting block 6 isgroovedin theupper face thereof to receive the" resistor conyolutions and coated, uponthe ,portion thereof to be exposedin'tlre furnace chain} ber,;with-a refractory materiallQwhich has no chemical effect upon t liemetallic' resistor. :Siniilar the spaced blocks. 10 are i'coated to protect the lower portions of the resistor convolutions from chemical reaction with the acid refractory material.

The coating 12 may be of any suitable material which will not react chemically with the resistor and which has the necessary refractory qualities. In the present instance I prefer to use zirconium oxide which may be formed thereon by depositing chemically or electrolytically upon the refractory supports, a coating of zirconium which is subsequently changed into the oxide by oxidation.

Another method of forming said coating upon the refractor support is to immerse the support in a so ution of zirconium oxide powder which will. penetrate into the pores of the refractory.

With either of the above-described methods of coating the resistor support with the oxide, a close grained coating results which is sufficiently adherent to withstand the rough usage incident to furnace operation.

By my invention I have provided a means for preventing a chemical reaction between normally acid refractory resistor supports and the metallic resistors supported thereby.

\Vhile for purposes of description I have considered only a refractory support having an acid characteristic, it is clearly within the scope of the present invention to provide such a coating upon a refractory support having a basic characteristic if such characteristic produces a deleterious effect upon the resistor. Also, while I have shown a preformed sinuous resistor element and a specific shape of support obviously the shape or form of the resistor and of the refractory support is im material so far as the scope of the present invention is concerned.

Modifications may be made in my invention without departing from the spirit and scope thereof, and I desire therefore that and prevent warping and consequent shortonly such limitations be placed thereon as are imposed by the prior art and set forth in the appended claims.-

1 claim as my" invention:

1,. In an electric furnace, a resistance'heat ing element, refractory means of normally acid characteristic directly supporting said resistance element within said furnace, and means for shielding said resistance'el'eifi'i'nt from the deleterious effects occasioned by said acid refractory supports.

2. In an electric furnace, a resistance heating clement, refractory means of normally acid characteristic for supportingsaid resist ance element-within said furnace, and a refractory coating of chemically neutral char acteristic upon said supporting means for preventing chemical reaction between said resistance element and support.

3. In an electric furnace, a met'allic resist ance heating element, refractory supporting means therefor of a normally acid characteristic, and a zirconium oxide coating formed upon said supporting means between said means and said resistance" element for prevcnt-in'g ch'enlical reaction the 'reli'ietween.

4'. In an electric furnace, an electric resist a-nce heatingelement,-refractory means directly supporting saidelement vit-liin said furnace, said means composed of a material Which'ch'emically reacts with said resistance element, and means between said sup-port and said resistance element for preventing said chemical reactions.

5; In an electrically hea'te'd device, the combination with a metal resistor and arefractory support therefor,- of a coating of zir conium oxide on said refractory support to revent chemical reaction between said'siipport and said resist-or.

In testimony fli rs-0f, Ilia ye hereunto suB-' scribed my minis-a Nuremberg this-13th day" JOHA N N SCHNEPF. 

